ref(Makefile): refactor `make dev-release`

This allows us to run `make -C controller config` when we know that
the image is pushed onto the registry and we just need to tell the
cluster to use this image.
fix(registry): make deis-cache mandatory

Sometimes the redis cache would take longer than the registry to come
up. In that case, confd would then set the host and port to be "",
in which case the registry would parse the YAML value as `None`. This
change makes the cache mandatory in order for the registry to come up.
chore(deisctl): remove redundant CHANGELOG.md

These commits are now included in the root CHANGELOG.md.
Merge pull request #2091 from mboersma/remove-deisctl-changelog

chore(deisctl): remove redundant CHANGELOG.md
fix(registry): use YAML's nil type
docs(managing_deis): update controller_settings.

Controller has itself as a dependency. Remove it.
Merge pull request #2096 from chuenlye/docs-update-controller-settings

docs(managing_deis): update controller_settings.
support for multiple make discovery-url runs
fix(controller/tests): add fleet socket to controller tests
feat(registry): image without development libraries to reduce the size.
ref(logger): just use go. remove bash script.
fix(logger): the test is expecting the message "deis-logger running".
fix(controller): properly serialize JSONField objects

JSONField is a finnicky thing. When serializing the object in the API,
it will just dump the object as a string. This ends in an invalid JSON
response. In the case of the Config object:

    {"owner": "bacongobbler", "app": "go", "values": "{\"HELLO\": \"world\"}", "memory": "{}", "cpu": "{}", "tags": "{}", ...}

This fix changes the JSON output to the following:

    {"owner": "bacongobbler", "app": "go", "values": {"HELLO": "world"}, "memory": {}, "cpu": {}, "tags": {}}

This is completely backwards compatible with previous requests. The
JSONSerializer will accept both strings and JSON objects in the request.
Merge pull request #2098 from cleblanc87/master

fix(Makefile): fix multiple make discovery-url runs
ref(logger): replace deis/go.
ref(project): replace deis/go with golang:1.3.
fix(controller): retrieve logs via GET request
fix(builder): properly parse config vars

Previously, the entire export from `jq` was considered one string, so
when we printed the output it would be like "-e HELLO=foo GOODBYE=bar".
This fixes it to "-e HELLO=foo -e GOODBYE=bar".

I also removed the for loop in favour of a list as bash invokes a
subshell in for loops, losing any data you set (such as BUILD_OPTS).
docs(README): add build status badge for CI test-master job
feat(client): add loading info msg to run command